1. Technical Field
This application relates to a milling cutter and method of operating same, and other machine tools, and an adjustment mechanism therefor.
2. Background Information
For metal-cutting machining of workpieces, both rotating tools, such as, for example, drills or milling cutters, and non-rotating tools, such as, for example, turning or firmer chisels are used.
In the manufacture of high-precision workpieces, a precise radial positioning of the cutting elements is often of decisive importance. Such as with rotating tools, the cutting elements being typically exchangeable cutting inserts which, according to the respective application, can also be designed as indexable inserts. The use of ground indexable inserts, which are very expensive, can be omitted when the fine-adjustment mechanism is used. In that case, one can use finish-sintered and, therefore, more cost-advantageous indexable inserts.
One example of a known milling tool with a fine-adjustment mechanism for the radial position of a cutting insert has a groove extending obliquely to the longitudinal axis of the tool and over the entire width of the tool is incorporated. In addition, a longitudinal slot is arranged centrally in the tool base body, crossing the bottom of the groove. An adjusting screw can be screwed into the groove from outside in radial direction, whereby the front part of the tool base body, on which the cutting insert is fastened, is bent outwards in radial direction. The groove and the longitudinal slot weaken the tool base body, so that the stability is impaired. Furthermore, this measure, by which the entire front portion of the tool base body is bent, allows the radial adjustment of one cutting insert only.
Another example of a known milling tool includes several cutting inserts, each of which is fastened on the tool base body by means of a cassette. The cassette itself again includes the groove and a slot extending across the bottom of the groove and having a circular cross-section. Here, too, a screw is screwed into the groove to fix the radial position. However, through the additional arrangement of a cassette, the required mounting space is relatively large and the number of required parts and their respective space requirements are high. With small tools, this variant is, therefore, unsuited.
A further example of a known fine-adjustment mechanism for a milling tool includes several adjusting portions distributed over the periphery of the base body, which are separated from the central base body through expanding openings and connected with the central base body through two marginal material bridges. Each of the adjusting portions carries a cutting insert. In radial direction, two supporting screws each pass through the adjusting portion, said screws resting against an eccentric roller extending in longitudinal direction. The fine positioning of the cutting insert is effected in this case by an adjustment of the eccentric roller acting against the supporting screws, so that these screws and with them, the entire adjusting portion is pushed radially outwards. Due to the chosen construction, the adjusting portion must be of solid design to guarantee sufficient stability. Therefore, this example is not suitable either for tools with small diameters.
There is also a known example of an arrangement of a clamping screw in a slot incorporated in the tool base body for clamping a cutting element in an insert seat. Here, however, no fine adjustment in radial direction, but only a clamping of the cutting insert is provided.